Have a look at the thread below:
Growing store bought lotus?

I am from z6a and I started growing lotus last year from tubers and from seeds. On container started from tubers, I used fertilizer tab, and on container started from seeds, I used the recipe from Joyce's lotus planting recipe http://forums2.gardenweb.com/discussions/1548701/lotus-barrel-pix-and-other-bowl-lotus-pix-for-rodney. The one that started from seeds did very well-it got 2 flowers.